Definition - What does Reactive Pigment mean?
A reactive pigment is a pigment that is capable of chemically reacting with other elements of the coating or the substrate. One of the most well-known reactive pigments, zinc oxide, reacts with free fatty acids in drying oils to form soap compounds. While the soaps created by this reactive pigment can affect adhesion, they can also help with efficient dispersing and wetting of pigments.
Corrosionpedia explains Reactive Pigment
Reactive pigments are included in paint and coating formulations to impart specific properties to the final product. Zinc oxide, for example, reacts with the fatty acids in oil paints to create soaps that help increase the paint's workability.
However, these soaps can form agglomerates or pustules that can negatively affect the appearance of the coating on the substrate. Furthermore, these soaps can migrate and gather at the interface between the coating and the substrate or adjacent coatings. As a result, excess soap production is linked with failures such as delamination and peeling.